Pulling apart the mid to late Cenozoic magmatic record of the Gulf of California : is there a Comondú arc?
Data(s) |
01/07/2013
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Resumo |
The composition of the lithosphere can be fundamentally altered by long-lived subduction processes such that subduction-modified lithosphere can survive for 100's Myrs. Incorrect petrotectonic interpretations result when spatial-temporal-compositional trends of, and source contributions to, magmatism are not properly considered. Western Mexico has had protracted Cenozoic magmatism developed mostly in-board of active oceanic plate subduction beneath western North America. A broad range of igneous compositions from basalt to high-silica rhyolite were erupted with intermediate to silicic compositions in particular, showing calc-alkaline and other typical subduction-related geochemical signatures. A major Oligocene rhyolitic ignimbrite “flare-up” (>300,000 km3) switched to a bimodal volcanic phase in the Early Miocene (~100,000 km3), associated with distributed extension and opening of numerous grabens. Extension became more focussed ~18 Ma resulting in localised volcanic activity along the future site of the Gulf of California. This localised volcanism (known as the Comondú “arc”) was dominantly effusive and andesite-dacite in composition. Past tectonic interpretations of Comondú-age volcanism may have been incorrect as these regional temporal-compositional changes are alternatively interpreted as a result of increased mixing of mantle-derived basaltic and crust-derived rhyolitic magmas in an active rift environment rather than fluid flux melting of the mantle wedge above the subducting Guadalupe Plate. |
Formato |
application/pdf |
Identificador | |
Publicador |
Geological Society of London |
Relação |
http://eprints.qut.edu.au/58549/1/58549A.pdf DOI:10.1144/SP385.8 Bryan, Scott Edward, Orozco-Esquivel, Teresa, Ferrari, Luca, & Lopez-Martinez, Margarita (2013) Pulling apart the mid to late Cenozoic magmatic record of the Gulf of California : is there a Comondú arc? Orogenic Andesites and Crustal Growth, 385. |
Direitos |
Copyright 2013 Geological Society of London |
Fonte |
School of Earth, Environmental & Biological Sciences; Science & Engineering Faculty |
Palavras-Chave | #040313 #040304 #040303 #040314 |
Tipo |
Journal Article |